Bottom-up Copper Deposition in Damascene Features Using Alkali Electrolytes

I will discuss deposition processes in patterned features such that filling starts towards the feature bottoms with deposition then proceeding upward. In particular I will present results for alkaline electrolytes that exhibit critical behavior in the presence of a single deposition-rate suppressing additive and, for deposition under conditions that take advantage of the critical behavior, exhibit localized filling within patterned features and bottom-up filling of those features. I will detail bottom-up filling during copper electrodeposition in submicrometer features. I will point out the electrochemical and feature filling characteristics shared with previously observed bottom-up filling with both copper and gold in TSVs by a mechanism based on the resistively stabilized negative differential resistance evident in the voltammetry for the electrolytes. I will also point out the differences from superfilling of fine features using the curvature enhanced accelerator coverage mechanism.